Urza, Prince of Kroog + Training Grounds + Mycosynth Lattice + Earthcraft

Urza, Prince of Kroog

Training Grounds

Mycosynth Lattice

Earthcraft

How it works

1. Activate the basic land by tapping it, adding 1.
2. Activate Urza by paying 4, creating a token copy of Training Grounds that is a 1/1 Soldier in addition to its other types.
3. Activate Earthcraft by tapping the Training Grounds token, untapping a basic land.
4. Activate the basic land by tapping it, adding 1.
5. Activate Urza by paying 2, creating a token copy of Training Grounds that is a 1/1 Soldier in addition to its other types.
6. Activate Earthcraft by tapping the Training Grounds token, untapping a basic land.
7. Activate the basic land by tapping it, adding 1.
8. Activate Urza by paying 1, creating a token copy of Training Grounds that is a 1/1 Soldier in addition to its other types.
9. Repeat from step 6.

This loop cleverly exploits the cost-reduction of Training Grounds to continually discount Urza, Prince of Kroog's ability to copy artifacts. Because Mycosynth Lattice turns everything on the board—including Training Grounds itself—into an artifact, Urza can make copies of the enchantment, and those copies count as creatures that Earthcraft can immediately tap to untap your lands. With each new copy of Training Grounds further reducing Urza's activation cost down to just one generic mana, you can infinitely cycle your mana to flood the board with an endless army of tapped Soldier token copies.